1 Department of Pediatrics, University Hospital Brno; Faculty of Medicine, Masaryk University Brno, Cernopolni 9, 662 63 Brno, Czech Republic.
2 Children's Heart Centre, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, V Uvalu 84, 150 06 Prague, Czech Republic.
3 Department of Radiology, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, V Uvalu 84, 150 06 Prague, Czech Republic.
4 Great Ormond Street Hospital for Children and Institute of Cardiovascular Sciences UCL, London, UK.